I purchased the origional battery and e-conversion kit back in 2020. It took several hours to figure out how to put it together, partly because you will need to make adjustments with washers so as to accommodate the hub to the front wheel forks and brake discs. Swytch are very good at communicating the best way to making fitting adjustments and they are also very good with replacing items that fail within the 2 year warranty period ( I purchased a USB rechargable back light that failed inside the warranty and Swytch replaced it without a quibble. I also needed to replace the battery cover due to a zip failure and that was done quickly aswell.) Nothing is perfect in life, or with rarity however, and the same could be said for Swytch. The early product would sometimes vibrate at the hub, at terminal speed, and still does, however, it is usually remedied by not peddling for a few seconds. It seems it had something to do with the power draw from the older battery, so I'm not sure if this has been cured with the new batteries. I would also say that I asked for information from Swytch about the battery charge duration of the new lighter weight products, but they failed to reply. Unless Swytch overlooked this, it suggests to me there was little or no advantage to making the conversion to the new battery, which to do so would have meant forking out another £300-400 depending on which one.